1. Field of the Invention
The present invention relates to a method of manufacturing a liquid discharge head, more particularly to a method of manufacturing a liquid path forming member of a liquid discharge head.
2. Related Background Art
In recent years, there have increasingly progressed miniaturization and densification of a liquid discharge head represented by an ink jet recording head. In the ink jet recording head in which an ink discharge port is disposed so as to face an energy generating element to generate energy for discharging ink, the energy generating element, an electric control circuit which drives this element and the like are formed on a substrate by use of a semiconductor manufacturing technology.
In a highly functional ink jet recording head, as a method of supplying the ink to a plurality of ink discharge ports (nozzles), there is adopted a structure in which an ink supply port is formed so as to extend through the surface and the back of the substrate, and an ink flow path is disposed so as to extend from the ink supply port to each discharge port. In a case where a silicon substrate is used as the substrate, as disclosed in U.S. Pat. No. 6,139,761, the ink supply port is often formed using a silicon anisotropic etching technology. In a case where a photosensitive resin is used as a liquid path forming member in which the ink flow paths and the discharge ports are formed, in order to increase a close contact force between the liquid path forming member and the silicon substrate, U.S. Pat. No. 6,390,606 discloses a constitution in which the liquid path forming member is bonded to the substrate via a adhesive layer made of a polyether amide resin.
On the other hand, as a method of manufacturing the liquid path forming member, as described in U.S. Pat. Nos. 6,139,761 and 6,145,965, there is known a method of disposing on the substrate a mold material which forms the flow path; coating this mold material with a resin which forms the liquid path forming member; forming the discharge port; and removing the mold material.
Moreover, in Japanese Patent Application Laid-Open No. 2005-104156, there is disclosed a manufacturing method of forming on the substrate a member which forms a side wall of the ink flow path; using positive photo resist a plurality of times; forming a sacrifice layer having a flat top in a space surrounded with the side wall of the ink flow path; and forming an orifice plate on the sacrifice layer. According to this specification, in this method, a shape and a dimension of the ink flow path are easily controlled, and a uniform ink flow path can be obtained.
However, the present inventors have manufactured the liquid discharge head by the method disclosed in Japanese Patent Application Laid-Open No. 2005-104156, and have found a case where the liquid path forming member peels from the substrate during use over a long period. It is considered that the adhesive layer is made of the polyether amide resin disclosed in U.S. Pat. No. 6,390,606 in order to improve a close contact property between the liquid path forming member and the substrate. However, since the polyether amide resin itself does not have any photosensitivity, steps become complicated. That is, in a case where the polyether amide resin is patterned, the photo resist is patterned to form a mask material, and the patterning needs to be performed by etching.